Considering progress in thin-film lumped-element integrated circuits construction and technology, expansion of lumped elements application in communication industry (cellular telephone), and common trend to miniaturization of lumped-element-related circuits, the overall dimensions and better adaptability to manufacture of the lumped elements are becoming their most important commercial characteristics. It is especially important for the circuits with low resonance frequency (f), where inductance (L) and capacitance (C) of the lumped elements should be high enough, according to the well-known relationship of ##EQU1## and therefore the influence of the parameters L and C on dimensions and fabrication of the elements is much higher.
In a conventional lumped element circular/isolator L is created by the so-called junction inductor which is in shunt connection with a separate capacitor (see, for example, the U.S. Pat. No. 4,812,787). Because of this shunt connection of the two separate entities (inductor and capacitor) the room in a circuit should be provided for both of these entities. Also, labor should be provided in order to produce those two entities, to put them in a circuit and to connect them with the rest of the circuitry.
It leads to lower level of integration of the circuit as well. The necessity to provide labor both for capacitor and inductor leads to higher fabrication cost.
It is desirable for a lumped circuit element to combine both L and C in the same entity, without any separation and connection. It is also desirable that the element mentioned would have higher reliability compared with the state-of-the art lumped elements. It is further desirable that the lumped circuit element would have low fabrication cost.